Pivotal clamping mechanism for die sets

ABSTRACT

A quick change clamping mechanism for metal working presses having upper and lower bolsters for supporting die components therebetween. The mechanism includes a clamping plate for mounting die components, articulated clamps pivotally mounted near one edge of each bolster, and opposing stops mounted near the opposite edge thereof. Each articulated clamp is activated by a piston component which produces pivotal movement to wedge the clamping plate between inwardly sloped shoulders on the clamp and opposing stop. The lower plate is supported for sliding movement into and out of the press when the clamps are released. Modifications include substituting a second pair of clamps for the stops and providing squared shoulders on coacting portion of the upper clamping components.

United States Patent 1 [111 3,834,217

Ducate Sept. 10, 1974 1 PIVOTAL CLAMPING MECHANISM FOR DIE SETS [76] Inventor: John S. Ducate, Suite 100, 800

Dutch Sq. Blvd., Verona, NJ. 29210 [22] Filed: Aug. 20, 1973 [21] Appl. No.: 389,592

Related US. Application Data [63] Continuation of Ser. No. 321,124, Jan. 5, 1973,

abandoned.

[52] US. Cl. 72/446, 72/462 [51] Int. Cl B21j 13/02 [58] Field of Search 72/462, 446, 448; 29/1 A [56] References Cited UNITED STATES PATENTS 2,036,483 4/1936 Lawrence 29/1 A 2,438,235 3/1948 Strom 29/1 A 2,755,758 7/1956 Johansen 72/462 2,955,347 10/1960 Zajac 29]] A 3,456,481 7/1969 Zeitlin... 72/446 3,610,021 10/1971 Hopper 72/446 FOREIGN PATENTS OR APPLICATIONS 1,194,227 6/1965 Germany 72/446 Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P. Crosby Attorney, Agent, or Firm-Townsend M. Belser, Jr.

[57] ABSTRACT A quick change clamping mechanism for metal working presses having upper and lowerbolsters for supporting die components therebetween. The mechanism includes a clamping plate for mounting die components, articulated clamps pivotally mounted near one edge of each bolster, and opposing stops mounted near the opposite edge thereof. Each articulated clamp is activated by a piston component which produces pivotal movement to wedge the clamping plate between inwardly sloped shoulders on the clamp and opposing stop. The lower plate is supported for sliding movement into and out of the press when the clamps are released. Modifications include substituting a second pair of clamps for the stops and providing squared shoulders on coacting portion of the upper clamping components.

12 Claims, 5 Drawing Figures PIVOTAL CLAMPING MECHANISM FOR DIE SETS This is a continuation of application Ser. No. 321,124 filed on Jan. 5, 1973, now abandoned.

BACKGROUND OF INVENTION The present invention is related to clamping devices for quickly changing die sets mounted between the bolsters of a stamping or other type of metal working press. The invention is particularly suitable for use in clamping standard die sets and associated die components in operative position on various types of equipment for shaping metal blanks.

With prior art techniques, the setting up of die sets in a press is a time-consuming operation due to the weight of a die set and its associated die components, the necessity of moving those components horizontally between the bolsters of the press and of then manipulating the upper and lower die plates into proper position in relation to their respective bolsters, and the tedious operation of maintaining proper alignment while clamping the die plates into operative position by a series of individual bolts and securing nuts. This complicated set-up procedure usually requires anywhere from half an hour to several hours to complete, depending upon the size of the press and the complexity of the die set. Although there are prior art devices with movable clamps to secure die plates in operative position, those devices require extensive mechanical linkages and related components which easily become misaligned or jammed and often fail completely, resulting in large percentages of down time for the press. Such attempts in the prior art to simplify set-up procedures for die sets have all resulted in relatively complicated equipment that is expensive to manufacture and maintain when compared to the present invention.

SUMMARY OF INVENTION The invention disclosed herein provides a novel pivotal clamping mechanism for mounting die sets in metal working presses and similar machines having an upper and a lower mounting bolster. In such machines, the upper bolster is usually driven in a reciprocating fashion by a hydraulically or mechanically actuated ram slidably mounted on guide slots or tracks supported upon the foundation of the machine. With the foregoing background and prior art in mind, a principal object of the present invention is to provide articulated clamping means pivotally mounted near one side of a press bolster and coacting with one or more stops rigidly secured to the bolster near the opposite side thereof so as to slidably receive a mounting plate therebetween and tightly clamp the plate in operative position on the bolster upon actuation of the clamping means. The clamping means includes an inwardly tapered or sloped shoulder and a piston mechanism to pivot that shoulder toward an outwardly tapered or sloped shoulder along the adjacent edge of the mounting plate and thereby produce a wedging action which firmly presses the plate against its adjacent bolster. The seating force generated by this wedging action is sufficient to overcome both the reverse biasing action of a spring release component and the load bearing tension of spring biased rollers in the lower bolster which support the die assembly for translational movement in relation to the press.

A primary object of the invention is therefore to provide a clamping mechanism for standard die sets wherein the die sets and associated components may be quickly installed, changed or replaced on a pressing machine in a matter of minutes.

Another object of the present invention is to provide novel clamping means for die sets in combination with means for easily moving and guiding complete die assemblies of substantial weight into proper operative position in a pressing machine when the clamping means is in its open position.

Another object of the invention is to provide a hydraulically or pneumatically operated mechanism for securely clamping into position both the upper die plate and the lower die plate of a die set with all of the associated die components in position between said plates.

A further object of the invention is to provide articulated clamps mounted for pivotal movement into their clamping position when actuated by means of a pneumatically or hydraulically operated piston component and into their open position upon release of pressure from said piston component by the biasing action of a spring means arranged to pivot said clamp in the direction opposite to that of said clamping movement.

A further object of the present invention is to provide a quick change device for standard die sets, which include upper and lower die plates, wherein a second or supplemental securing plate is adapted to coact with novel clamping components on the press bolster and to be secured to conventional die plates by recessed bolts or other means, such as welding, so that remounting of die components is avoided, thus permitting an easy and inexpensive changeover from existing clamping devices to the present invention and the use of valuable standard die sets already on hand.

Another object of the present invention is to provide a quick change clamping mechanism for the dies of a metal working press wherein proper alignment of the upper and lower die shoes is attained through the use of the conventional guide pins of standard die sets.

Another object of the present invention is to provide an articulated clamp requiring a minimum of physical movement between its open and closed positions and having a compact construction which includes as an integral part thereof the actuating mechanism producing the clamping forces.

A further object of the present invention is to minimize the number of articulated clamps in the clamping mechanism by utilizing rigidly secured opposing stops instead of actuated opposing clamps and to accurately and positively position a given die set in the same operative position each time the set is reinserted in the press following its removal for the use of a different die set.

Another object of the present invention is to provide a quick change clamping mechanism for press machines compatible with die change lift trucks and other devices for transporting die sets to, inserting die sets in, and removing die sets from a press.

A further object of the present invention is to provide a quick change clamping mechanism which may be installed on the bolsters of existing metal working presses by machining appropriate channels and recesses therein for mounting the articulated clamps, the opposing stops, and the lower die plate supporting rollers.

A further object of the present invention is to provide a device for clamping metal working dies to a press apparatus wherein each die is firmly secured to its corresponding bolster by the clamping action of a pivotal clamp having an inner surface which engages a coacting portion of a mounting plate when actuated by fluid pressure.

Another object of the invention is to provide spring means for readily dismounting each die set by utilizing spring tension to free the die mounting components from their operative position on the bolsters of the press.

Another object of the present invention is to provide a compact clamping means for presses which does not require any protruding members except flexible fluid pressure hoses at one side of the press, hence avoiding rigid protruding members and providing free space on three sides of the press in which an operator may work freely.

A still further object of the present invention is to provide a fluid pressure operated clamping device useable with a wide variety of metal forming and piercing diepresses and having a simple and compact construction capable of producing ample clamping pressure to hold heavy mounting plates and associated die components accurately in position upon the press bolsters during metal working operations.

Still another object of the invention is to provide a quick change clamping mechanism for standard die sets that prevents misalignment between upper and lower die components and excessive wear of associated die shoe guide pins.

A further object of the invention is to provide die set clamping mechanisms for existing metal working presses wherein the position of the clamping components can be quickly changed to accommodate die sets of different sizes and die plates of different widths.

In addition to the numerous advantages apparent from the foregoing discussion, the present invention has the further advantages of simplicity, ruggedness, durability and ease and economy of construction and manufacture. Although the clamp itself is a specialized part, the mounting and actuating elements thereof can be constructed from standard parts which are commer cially available and the entire mechanism can be assembled with relatively few machinings with known machine tools. The exact nature of the invention as well as other objects and advantages thereof will be readily apparent from the annexed drawings and the following specific description of the preferred embodiments of the invention.

DESCRIPTION OF DRAWING For a better understanding of the present invention, reference is made to the accompanying drawings in which:

FIG. 1 is a diagrammatic front elevational view of a metal working press employing a conventional die set and utilizing the clamping mechanism according to the present invention.

FIG. 2 is a diagrammatic side elevational view of the metal working press of FIG. 1 further illustrating the clamping mechanism according to the present invention.

FIG. 3 is a fragmentary sectional view showing the construction details of an articulated clamp and a spring loaded support roller of the present invention,

the support roller being held in its depressed position by the clamping action of the pivotal clamp which is shown in its engaged or actuated position.

FIG. 4 is a diagrammatic front elevational view of a metal working press showing a modification of the clamping mechanism of FIG. 1.

FIG. 5 is a fragmentary sectional view showing the construction details of the modified upper articulated clamps utilized in the clamping arrangement of FIG. 4.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT For purposes of illustration, the present invention has been shown in the drawings as mounted upon a conventional stamping press for forming sheet metal parts using a die set of standard design. However, the invention is adaptable for use with many other types of metal working machines, including lancing and piercing apparatus, and can be used to hold almost any plate supported tool or die component in operative position upon its associated bolster, platen, rarn or equivalent support structure, utilization of the design features of the invention permitting quick replacement of a wide variety of such tools.

The press to which the present invention is attached consists of the usual bed 10 and an upper head or ram 12, the former being fixed and the latter being supported for up and down reciprocal movement along the posts 14 under the drive of an hydraulic or pneumatic actuator or other drive means. The particular drive means for the ram or upper platen is not shown, it being understood that the invention is not directed to the press itself or its operating drive.

Secured to the reciprocating ram 12 is an upper bolster 20 and secured to the fixed bed 10 is a lower bolster 30. With reference particularly to FIG. 1, at least one, and preferrably two, stops 21 are rigidly secured along one transverse (depth direction) side of the bolster 20 by a bolt 22, the stop having an inwardly tapered or sloped shoulder 23 and being accurately located in a fixed longitudinal position by means of a machined ridge-like projection 24 fitted within a machined channel or slot 25 in the bolster itself.

Along the transverse bolster edge opposite to the fixed stops 21 are a pair of articulated clamps having a body portion 40 pivotally mounted on the bolster by means of a bulb-shaped projection or pivot knob 42 rotatably fitted within a transversely extending channel 44 of bulbous cross-section conforming to the shape of knob 42, the entrance sides 45-45 of the channel providing sufficient clearance for the neck portion 43 of the bulbous projection to permit tilting of the entire clamp body as best illustrated in FIG. 3 of the drawings. For purposes of further explanation hereinafter, a prime superscript will be used with the same numerical designation to indicate the lower press and clamping components since the upper and lower components of the first described embodiment are identical for purposes of explanation.

With reference to FIG. 3, the clamp 40 is actuated to the closed or clamping position by means of a fluid piston 46' having an outer rounded and smooth bearing surface 47 adapted to act against the lower bolster surface 32'. Fluid pressure is supplied to an integral piston cylinder 48' within the clamp body 40' by means of hose 49' which communicates with the cylinder as illustrated in FIG. 3. The source of hydraulic or pneumatic fluid pressure is of conventional design and is not shown.

The clamp body also includes an integral lever arm portion 50 which extends inwardly beyond the pivotal axis 41 of the retaining knob 42 on the side of the clamp body opposite to that containing the piston cylinder, the piston side of the clamp constituting a second pivotal lever arm. Mounted on the inwardly projecting lever arm 50' is a spring loaded plug element 52 arranged for reciprocal movement within a recess 53'. The reciprocating plug 52' projects downwardly through aperture 58' and is biased against the lower bolster surface 32' by a spring means 54' held within the recess 53' by a set screw component 56' which is threaded within the upper portion of the recess to permit adjustment of spring tension. At the inner edge of the arm 50 is an inwardly sloped or tapered surface 57' which coacts with an adjacent outwardly sloped or tapered surface 61 on a die set clamping or securing plate 60. Both surfaces are tapered at a 45 angle in the preferred embodiment.

When fluid under pressure is supplied to cylinder 48 through line 49, the piston 46 is pushed or driven against the bolster surface 32 causing the articulated clamp 40' to pivot or tilt to its closed or clamping position, clamp surface 57' and stop surface 23' wedging against plate surfaces 6l-61 to force plate 60' flush against the outer bolster surface 32' and firmly lock the clamping plate on the bolster in proper alignment for subsequent mating of upper and lower die shoe components. Upon release of pressure acting on the fluid medium, the pressurizing fluid flows out of chamber 48, allowing the biasing plug 52 to tilt or pivot the clamp body 40' in the reverse direction to free the securing plate 60'. The tension of spring means 54, which is adjustable by set screw 56', provides sufficient driving force through reciprocating plug 52' and lever arm 50 to cause the fluid to flow out of chamber 48 and to tilt the clamp body in the reverse direction from that pivotal movement induced by the clamping action of actuating piston 46'.

With reference to FIG. 1 of the drawings, the die plates of a standard die set, which is generally designated 70, are fastened to the clamping plates 60 and 60' of the present invention by means of a series of recessed bolts or the like 55 and 55'. The die set 70 consists principally of upper and lower die plates 72 and 72', a pair of catercomer guide pins 74-74, and upper and lower die shoe components 76 and 77. It is to be understood that the die set 70 and the related die components are of a standard commercial design in the preferred embodiment. However, it is contemplated that for a custom made die set, the upper die plate 72 and the upper clamping plate 60 could be made as a single integral unit which would then be referred to merely as a die plate. Similarly, the equivalent lower components 72' and 60 could be made as an integral lower die late.

p Another important feature of the present invention is the supporting ball roller mechanism generally designated 80. As illustrated in FIGS. 1 and 2 of the drawings, there are preferrably a total of 6 such roller mechanisms utilized in the lower bolster, although a minimum of four (4) or a larger number of roller mechanisms may be provided as necessary to support the weight of the two clamping plates 60 and 60' and all intervening die set components. With reference to FIG. 3 for the details of construction, a ball roller 81 is secured in a recess 82 in the lower bolster 30 by means of an apertured disk 83 threaded within a counterbore 84. The disk 83 has an inner tapered bore 87 adapted to permit the roller ball 81 to project a sufficient distance above the bolster surface 32' to raise the inner surface of plate 60' completely clear of the adjacent bolster when the articulated clamp is in its open position. The ball roller 81 is biased strongly outward by a spring means 89 having sufficient tension for each individual ball roller to support its proportionate share of the weight of the complete die assembly. Thus, when the articulated clamps are released, the entire die assembly is freed from engagement with the bolsters and movably supported upon a series of ball rollers for easy translational movement into or out of clamping position between the upper bolster 20 and the lower bolster 30. The series of six (6) ball rollers is preferably arranged in three longitudinal rows as seen in FIG. 2 and two transverse rows as seen in FIG. 1, the directions referred to being in relation to the longest or front dimension of the bolster (the longitudinal axis running from side to side).

In using the novel device of the present invention, a standard upper die plate 72 is mounted upon the upper clamping plate 60 by means of recessed threaded bolts 55, and the standard lower die plate 72 is mounted upon the lower clamping plate 60 by means of recessed threaded bolts 55'. The other components of the die set are then assembled on each die plate and the upper and lower die assemblies are engaged with the upper die shoe resting in mating relationship upon the lower die shoe as guided into position by guide pins 74-74.

The completed die assembly is then transported to the edge of a metal working press in which the upper slide or ram has been adjusted to a stroke down position that provides suflicient clearance between the upper and lower bolsters for insertion of the assembly with the upper clamping plate 60 sliding between and above the inwardly sloped surfaces of the upper articulated clamps 40 and associated stops 21, and the lower clamping plate 60 sliding between and below the inwardly sloped surfaces of the lower articulated clamps 40' and associated stops 21 The absence of any metal work between the dies allows sufficient space for easy insertion and removal of the complete die assembly, which includes the clamping plates secured at the upper and lower extremes thereof.

When the bolsters of the press are properly positioned, the complete die assembly slides transversely into position between the upper and lower bolsters while resting upon and being supported by the spring loaded ball rollers 81 in the lower bolster 30, the tensioning force of the springs 89 loading those rollers sufficiently to movably support the die assembly off of the lower bolster surface 32'. The die assembly is inserted in the press by pushing it transversely into the vertical space between the bolsters and the horizontal space between the opposing faces of the fixed stops on one side and the articulated clamps on the other side. Transverse or rearward movement of the assembly continues until the lower clamping plate 60' abuts a series of fixed posts or pins 34 along the rear edge of the lower bolster 30 as illustrated in FIG; 2 of the drawing. The die assembly is then in the correct transverse and longitudinal position for operation of the novel clamping mechanism of the present invention.

The upper and lower articulated clamps 40 and 40' are then actuated by fluid pressure to jam or wedge the clamping plates between the sloped faces 23 and 23' of the stops and the sloped opposing faces 57 and 57' of the clamps, respectively. This jamming or wedging action will cause the entire die assembly to shift slightly toward the stationary stops 21 and 21' so as to wedge the adjacent sloped faces of the plates firmly against and under, the coacting stop surfaces 23 and 23', bringing each inner clamping plate surface flush with the adjacent outer bolster surface. The wedging motion of the articulated clamps is caused by the pivotal or tilting movement of the clamp body under the rotational force generated by the action of fluid pistons 46 and 46' thrusting against adjacent bolster surfaces. With reference to FIG. 3, this clamping motion is in a counterclockwise direction and wedges the sloped face 57' of the clamp 40 against the adjacent sloped face 61' extending transversely along the edge of clamping plate 60. This wedging action between slanted bearing surfaces has a vertical component which causes the lower clamping plate 60' to depress the spring loaded ball rollers 81, the clamping pressure being sufiicient to overcome both the roller spring tension and the release plug spring tension and securely hold the plate against the adjacent bolster surfaces in a flush frictional relationship. In this embodiment, the wedging action of the upper clamping components is the same.

The press ram is then adjusted to proper operating height and the metal blank to be worked on inserted between the die shoes, with normal metal forming operations following thereafter. From the foregoing, it is apparent that the entire die assembly 70 may be quickly replaced by another die assembly accurately positioned for a new metal working operation. If a number of diflerent metal working operations are anticipated, the die assembly for each operation is made up as previously described and a change in die setups may be performed within a period of several minutes, whereas conventional die setup changes of this type take from between thirty minutes to several hours. Through the use of standard die sets with their associated guide pins in combination with the precision alignment afforded by the stops 2] and 21' and the rear posts 34, both the upper and lower die elements of the die set will be accurately located and securely held in position for subsequent metal working operations of the press.

With reference to FIGS. 4 and 5 of the drawings, a modified pivotal clamping arrangement is illustrated for the upper die components. In this embodiment, the body of articulated clamps 104 is of a modified construction and the fixed stop 21 of FIG. 1 has been replaced by an articulated opposing clamp 120 of the same construction as clamp 104. When this modified clamping mechanism is used, both the upper bolster 20 and the lower bolster 30 are preferrably of approximately the same width as illustrated in FIG. 4. Although both the articulated clamps and the clamping plate for the upper bolster of FIG. 4 are of a different design than in FIG. 1, it is to be understood that the lower bolster clamping arrangement remains unchanged and is as previously described.

In the modified upper clamping embodiment, the tapered coacting surfaces machined on the clamping plate and on the articulated clamp body of FIG. 1 have been eliminated. Instead, upper pivotal clamp 104 has a squared shoulder 105 milled out of the clamp body at a 90 cut to produce a horizontally disposed inner clamping surface 106. A bulb-shaped projection or pivot knob 112 is attached to the clamp body 104 by neck portion 111, the pivot knob 112 being rotatably mounted within a conforming channel 114 of bulbous cross section cut transversely through the upper bolster 20 in the same manner as for the articulated clamps 40 and 40 previously described. Similarly, articulated clamp 104 is activated by a fluid piston 108 mounted within the clamp body so as to thrust against the upper bolster surface 32. However, no reciprocating spring biased plug, similar to plug 52 of clamp 40, is employed since the weight of the upper securing plate and the die components mounted thereon provides sufficient force to tilt the clamp body in the reverse direction upon release of the pressure acting on piston 108, automatically freeing the upper securing plate 130 for removal from the press upon deactivation of the piston actuating means. Upper opposing clamp is of identical construction. The modified upper clamping plate has squared shoulders along its opposing edge portions as defined by the juncture of outer horizontal surface 122 and vertical side surfaces 121-421, neither of which needs to be machined with any high degree of accuracy.

When readying the press for operation with the modified clamping assembly, the complete die assembly with clamping plates attached slides transversely into the press on the spring loaded ball rollers 81 until the clamping position is reached with the rear surface of the lower clamping plate 60 abutting the transverse positioning pins 34 along the rear edge of lower bolster 30, all as previously described. A modified clamping sequence is then employed wherein the lower articulated clamps 40 are first actuated to wedge the lower clamping plate 60' between the tapered faces 23' of the lower stops 2l-2l and the tapered faces 57' of the lower articulated clamps 4040'. This initial wedging action shifts the entire die assembly slightly toward the stationary stops 21 and brings the lower clamping plate 60 flush with the adjacent lower bolster surface 32' as explained above. During this translational movement of the lower clamping plate, the usual guide pins 74--74 automatically keep the upper die components, together with the upper clamping plate 130 which is rigidly secured thereto, in proper alignment with the lower die components. Upper pairs of articulated clamps 104-104 and 120-120 are then activated in unison to cause the clamping surface 106 of each clamp to frictionally engage the outer surface 122 of the upper clamping plate 130, forcing it vertically upward into flush frictional engagement with the outer surface 32 of upper bolster 20 without any further horizontal shifting or movement.

Thus, the modified upper articulated clamps 104 and 120 exert only a vertical clamping force component upon the upper securing plate 130. The absence of any horizontal force component on the upper plate eliminates the tendancy for misalignment between the upper and lower plates which has been found to occur when employing the embodiment of FIGS. 1 3 on large presses where distances between articulated clamps and fixed stops have to be relatively great. Such misalignment can result in scraping and strain on guide pins 74-74, causing them to wear excessively and unevenly with subsequent misalignment of die components. In the modified clamping arrangement described, the entire die assembly is locked in a preset longitudinal position determined only by the location of the fixed lower stops 21'.

As best illustrated in FIG. 4, both the upper and lower bolsters of the press may have auxiliary channels so that both the articulated clamps and the fixed stops can be moved further outboard (i.e., further apart longitudinally) to accommodate larger die sets, the mounting of which requires wider clamping plates. Thus, with reference to FIG. 4, an auxiliary channel 90' of the same bulbous cross-sectional shape as channel 44' may be provided in the lower bolster so that the articulated clamps may be removed from channel 44 and placed further outboard in channel 90'. Similarly, auxiliary slot 95 and auxiliary threaded apertures 96 may be provided in the bolster 30 so that the stop 21 can also be moved further outboard to accommodate lower clamping plates of substantially greater width. Auxiliary channels 116 may also be provided in the upper bolster of FIG. 4 so that the modified articulated clamps 104 and 120 can be moved outboard to accommodate a wider upper securing plate in place of plate 130. Similar auxiliary channels and slots may be employed for the upper clamps and stops of FIG. 1.

Operation of the press from the standpoint of metalworking operations is entirely conventional after the die assembly has been clamped in position utilizing the novel mounting and clamping devices of the present invention. Thus, the metal working operation continues as each blank is inserted in and removed from the press following each reciprocating action of the press ram. The clamping forces provided by the invention are more than sufficient to keep the upper and lower portions of the die assembly firmly secured to their associated bolsters.

When a die assembly change is desired, the press ram is again stopped in its down stroke position without any work between the die surfaces. A solenoid operated valve (not shown) is then actuated to release the clamping pressure on the fluid in the piston cylinders of the clamps. With reference to FIG. 3 of the drawing, as the clamping pressure is released, the clamp 40' is pivoted clockwise by the spring loaded plug 52 into its open position, thereby releasing both the vertical and horizontal compressive forces holding the clamping plate 60' in position on the bolster. Although spring loaded, reverse acting plugs may also be utilized in the upper clamps, the weight of the die assembly will free the upper clamping plate as discussed in connection with the modified upper clamping structure. Also, as the pressure is released, the spring loaded rollers 81 in the lower bolster will lift the bottom securing plate 60' off of the bolster surface, leaving the complete die assembly free and movably supported for removal from between the press bolsters. Upon release of the clamps the entire die assembly is then moved transversely off of the lower bolster and onto a conventional die set transporting device placed at the forward edge of the bolster. A new die assembly can then be inserted following the same mounting procedure set out hereinabove.

Although only a few embodiments of the present invention have been described, other embodiments and variations will occur to those skilled in the art. It is possible, of course, to use various features of the specific embodiments, either separately or in various combinations. Thus, it is possible to mount almost any combination of die assemblies or other tooling or metal working components upon a press bed using the clamping mechanisms of the present invention. Such uses are clearly within the contemplation of the present invention. Furthermore, many structural changes are possible and are intended to be within the scope of this disclosure. It is also to be understood that the attached drawings and the foregoing specification merely illustrate and describe the preferred embodiments of the invention and that other embodiments are contemplated within the scope of the appended claims.

I claim:

1. In a metal working apparatus having one or more bolsters for supporting metal shaping die components, a clamping mechanism for securing die components in operative position upon a bolster, comprising:

a. a clamping plate having outwardly sloped shoulders along two opposing edges thereof in a spaced relationship approximating two opposing nonparallel sides of a trapezoid;

b. means for rigidly securing die components to said clamping plate;

0. stop means rigidly secured to said bolster near one edge thereof and having an inwardly sloped shoulder adapted to coact with one of the sloped shoulders of said clamping plate;

d. clamping means pivotally mounted upon said bolster near the opposite edge thereof and including a body having an inwardly sloped shoulder adapted to coact with the other outwardly sloped shoulder of said clamping plate and with said stop means to wedge said clamping plate between the sloped shoulders of said stop means and said pivotal clamping means; and

. means for actuating said clamping means to pivot the clamp body so that said clamp shoulder moves toward said coacting plate shoulder and wedges said clamping plate firmly against the shoulder of said stop means and flush upon the surface of said bolster in operative position.

2. A clamping mechanism as claimed in claim 1 wherein said clamping means also includes a spring means biasing said clamping means for reverse pivotal movement opposite to that produced by said actuating means, the biasing force of said spring means causing sufficient reverse pivotal movement upon deactivation of said clamp actuating means to release said clamping plate from its wedged position and free it for translational movementin relation to said bolster.

3. A clamping mechanism as claimed in claim 1 wherein a series of at least four roller means are recessed within the outer bolster surface at locations adjacent to the inner surface of said clamping plate and arranged so that each roller is in position to support a proportionate share of the total weight of all die plates and components, said roller means having a freely rotatable bearing portion adapted to project a substantial distance above said bolster surface and a spring means biasing said bearing portion above said bolster surface with sufiicient force to support said proportionate die assembly weight and maintain said clamping plate free of the bolster surface when said clamping means is deactivated.

4. A clamping mechanism according to claim 1 wherein said clamp actuating means is comprised of a piston mounted within an actuating cylinder in said clamp body and adapted to thrust against said bolster when activated to forcefully pivot said clamp shoulder toward said coacting plate shoulder to wedge said clamping plate in operative position.

5. A clamping mechanism according to claim I mounted upon a first bolster of a metal working apparatus and a second clamping mechanism according to claim I mounted upon a second bolster of the same apparatus in spaced relation to said first clamping mechanism; said bolsters being arranged for reciprocal movement toward and away from each other and said second clamping mechanism being adapted to secure die components on said second bolster in operative position to coact with die components secured in operative position on said first bolster during reciprocal movement of said bolsters, the coaction between said first and second die components producing metal shaping operations on metal blanks inserted therebetween.

6. In a metal working machine having a lower bolster to support the lower die plate of a die set and an upper bolster to support the upper die plate of a die set, a die set clamping device comprised of lower and upper clamping plates adjacent to said lower and upper bolsters, respectively, each plate having outwardly sloped surfaces along two opposing edges thereof; means for rigidly securing said upper clamping plate to the upper die plate and said lower clamping plate to the lower die plate; stop means rigidly mounted near one edge of each of said bolsters and having an inwardly sloped face adapted to frictionally engage one of said outwardly sloped plate surfaces; and pivotal clamping means including a body portion rotatably mounted near the opposite edge of each of said bolsters for pivotal movement toward and away from said stop means and having an inwardly sloped clamping face adapted to frictionally engage the other outwardly sloped plate surface, activating means arranged to forcefully pivot said clamp body toward said opposing stop means and bring said clamping face into engagement with said sloped plate surface so as to wedge each clamping plate upon its respective bolster between the sloped faces of said stop means and said clamping means, and spring means adapted to pivot said lower clamp body away from said opposing stop means with sufficient force to release said lower clamping plate from said wedging action upon deactivation of said activating means.

7. In a metal working apparatus having a lower bolster to support the lower die components of a die set and an upper bolster to support the upper die components of a die set, a die set clamping device comprising:

a. a lower clamping plate having outwardly tapered faces along two opposing edges thereof;

b. stop means rigidly secured to the lower press bolster near one edge thereof and having an inwardly tapered face arranged to frictionally engage one of the tapered faces of said lower clamping plate;

c. lower clamping means pivotally mounted upon said lower bolster near the edge opposite said stop means and including a body having an inwardly tapered face arranged to frictionally engage the other outwardly tapered face of said lower clamping plate, and actuating means arranged to pivot said clamp body toward said opposing stop means and bring said clamp face and said stop face into frictional engagement with said plate faces to wedge the lower plate into operative position upon the lower bolster between said stop means and said lower clamping means;

d. an upper clamping plate with substantially squared edges along two opposing sides thereof, each edge having an outer clamping surface;

upper clamping means including a first clamp body pivotally mounted upon said upper press bolster near one edge thereof and having an inwardly projecting shoulder with an inner clamping surface arranged for normal clamping engagement with the outer clamping surface of one of the squared edges of said upper clamping plate, a second clamp body pivotally mounted upon said upper press bolster near the edge opposite said first clamp body and having an inwardly projecting shoulder with an inner surface arranged for normal clamping engagement with the outer clamping surface of the other squared edge of said upper clamping plate, and actuating means arranged to pivot said upper clamp bodies toward each other and bring said inner clamp surfaces into normal engagement with said outer plate surfaces to clamp the upper plate into operative position upon the upper bolster between said opposing clamp bodies; and

f. means for rigidly securing the lower die components to the lower clamping plate and the upper die components to the upper clamping plate.

8. A die set clamping device as claimed in claim 7 wherein means is provided for actuation of said upper clamping means after said lower clamping plate has been wedged into operative position by prior actuation of the lower clamping means.

9. A clamping mechanism as claimed in claim 7 wherein said lower clamping means also includes a spring means biasing said clamp body for reverse pivotal movement opposite to that produced by said actuating means, the biasing force of said spring means causing sufficient reverse pivotal movement upon deactivation of said lower clamp actuating means to release the lower clamping plate from its wedged position and free it for translational movement in relation to the lower bolster.

10. A clamping mechanism as claimed in claim 7 wherein a series of at least four roller means are recessed within the outer surface of the lower bolster at locations adjacent to the inner surface of the lower clamping plate and arranged so that each roller is in position to support a proportionate share of the total weight of all clamping plates and die components, said roller means having a freely rotatable bearing portion adapted to project a substantial distance above said bolster surface and a spring means biasing said bearing portion above said bolster surface with sufficient force to support said proportionate die assembly weight and maintain said lower plate free of the lower bolster surface when said clamping means is deactivated.

11. A clamping mechanism according to claim 7 wherein said clamp actuating means includes a piston mounted within an actuating cylinder in each clamp body and arranged to thrust against the clamp mounting bolster when activated to forcefully pivot the engaging surface of the clamp body against the engaged surface of the associated clamping plate.

12. In a metal working apparatus having at least one bolster for supporting metal working die components, a clamping mechanism for securing die components in operative position upon the bolster comprising a clamping plate having an outer clamping surface along each of two opposing edges thereof; clamping means including a first clamp body pivotally mounted upon said bolster near one edge thereof and having an inner clamping surface arranged to coact in clamping engagement with one of the outer clamping surfaces on the clamping plate and a second clamp body pivotally mounted upon said bolster near the edge opposite said first clamp body and having an inner clamping surface ing plate.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 834 Z17 Dated September 10 1974 Inventor(s) John. te

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet item [76] should read --'John S. Ducate- Suite 100 800 Dutch Square Boulevard Columbia, South Carolina 29210 Signed and sealed this 11th day of February 1975.

' (SEAL) Attest: I C. MARSHALL DANN RUTH MASON Commissz'noner of Patents Attesting Officer and Trademarks FORM P USCOMM-DC 60376-P69 u.s. covznuuam mmrms omcz; a69 93 

1. In a metal working apparatus having one or more bolsters for supporting metal shaping die components, a clamping mechanism for securing die components in operative position upon a bolster, comprising: a. a clamping plate having outwardly sloped shoulders along two opposing edges thereof in a spaced relationship approximating two opposing nonparallel sides of a trapezoid; b. means for rigidly securing die components to said clamping plate; c. stop means rigidly secured to said bolster near one edge thereof and having an inwardly sloped shoulder adapted to coact with one of the sloped shoulders of said clamping plate; d. clamping means pivotally mounted upon said bolster near the opposite edge thereof and including a body having an inwardly sloped shoulder adapted to coact with the other outwardly sloped shoulder of said clamping plate and with said stop means to wedge said clamping plate between the sloped shoulders of said stop means and said pivotal clamping means; and e. means for actuating said clamping means to pivot the clamp body so that said clamp shoulder moves toward said coacting plate shoulder and wedges said clamping plate firmly against the shoulder of said stop means and flush upon the surface of said bolster in operative position.
 2. A clamping mechanism as claimed in claim 1 wherein said clamping means also includes a spring means biasing said clamping means for reverse pivotal movement opposite to that produced by said actuating means, the biasing force of said spring means causing sufficient reverse pivotal movement upon deactivation of said clamp actuating means to release said clamping plate from its wedged position and free it for translational movement in relation to said bolster.
 3. A clamping mechanism as claimed in claim 1 wherein a series of at least four roller means are recessed within the outer bolster surface at locations adjacent to the inner surface of said clamping plate and arranged so that each roller is in position to support a proportionate share of the total weight of all die plates and components, said roller means having a freely rotatable bearing portion adapted to project a substantial distance above said bolster surface and a spring means biasing said bearing portion above said bolster surface with sufficient force to support said proportionate die assembly weight and maintain said clamping plate free of the bolster surface when said clamping means is deactivated.
 4. A clamping mechanism according to claim 1 wherein said clamp actuating means is comprised of a piston mounted within an actuating cylinder in said clamp body and adapted to thrust against said bolster when activated to forcefully pivot said clamp shoulder toward said coacting plate shoulder to wedge said clamping plate in operative position.
 5. A clamping mechanism according to claim 1 mounted upon a first bolster of a metal workIng apparatus and a second clamping mechanism according to claim 1 mounted upon a second bolster of the same apparatus in spaced relation to said first clamping mechanism; said bolsters being arranged for reciprocal movement toward and away from each other and said second clamping mechanism being adapted to secure die components on said second bolster in operative position to coact with die components secured in operative position on said first bolster during reciprocal movement of said bolsters, the coaction between said first and second die components producing metal shaping operations on metal blanks inserted therebetween.
 6. In a metal working machine having a lower bolster to support the lower die plate of a die set and an upper bolster to support the upper die plate of a die set, a die set clamping device comprised of lower and upper clamping plates adjacent to said lower and upper bolsters, respectively, each plate having outwardly sloped surfaces along two opposing edges thereof; means for rigidly securing said upper clamping plate to the upper die plate and said lower clamping plate to the lower die plate; stop means rigidly mounted near one edge of each of said bolsters and having an inwardly sloped face adapted to frictionally engage one of said outwardly sloped plate surfaces; and pivotal clamping means including a body portion rotatably mounted near the opposite edge of each of said bolsters for pivotal movement toward and away from said stop means and having an inwardly sloped clamping face adapted to frictionally engage the other outwardly sloped plate surface, activating means arranged to forcefully pivot said clamp body toward said opposing stop means and bring said clamping face into engagement with said sloped plate surface so as to wedge each clamping plate upon its respective bolster between the sloped faces of said stop means and said clamping means, and spring means adapted to pivot said lower clamp body away from said opposing stop means with sufficient force to release said lower clamping plate from said wedging action upon deactivation of said activating means.
 7. In a metal working apparatus having a lower bolster to support the lower die components of a die set and an upper bolster to support the upper die components of a die set, a die set clamping device comprising: a. a lower clamping plate having outwardly tapered faces along two opposing edges thereof; b. stop means rigidly secured to the lower press bolster near one edge thereof and having an inwardly tapered face arranged to frictionally engage one of the tapered faces of said lower clamping plate; c. lower clamping means pivotally mounted upon said lower bolster near the edge opposite said stop means and including a body having an inwardly tapered face arranged to frictionally engage the other outwardly tapered face of said lower clamping plate, and actuating means arranged to pivot said clamp body toward said opposing stop means and bring said clamp face and said stop face into frictional engagement with said plate faces to wedge the lower plate into operative position upon the lower bolster between said stop means and said lower clamping means; d. an upper clamping plate with substantially squared edges along two opposing sides thereof, each edge having an outer clamping surface; e. upper clamping means including a first clamp body pivotally mounted upon said upper press bolster near one edge thereof and having an inwardly projecting shoulder with an inner clamping surface arranged for normal clamping engagement with the outer clamping surface of one of the squared edges of said upper clamping plate, a second clamp body pivotally mounted upon said upper press bolster near the edge opposite said first clamp body and having an inwardly projecting shoulder with an inner surface arranged for normal clamping engagement with the outer clamping surface of the other squared edge of said upper clamping plate, and actuating means arranged to pivot said upper clamp bodies toWard each other and bring said inner clamp surfaces into normal engagement with said outer plate surfaces to clamp the upper plate into operative position upon the upper bolster between said opposing clamp bodies; and f. means for rigidly securing the lower die components to the lower clamping plate and the upper die components to the upper clamping plate.
 8. A die set clamping device as claimed in claim 7 wherein means is provided for actuation of said upper clamping means after said lower clamping plate has been wedged into operative position by prior actuation of the lower clamping means.
 9. A clamping mechanism as claimed in claim 7 wherein said lower clamping means also includes a spring means biasing said clamp body for reverse pivotal movement opposite to that produced by said actuating means, the biasing force of said spring means causing sufficient reverse pivotal movement upon deactivation of said lower clamp actuating means to release the lower clamping plate from its wedged position and free it for translational movement in relation to the lower bolster.
 10. A clamping mechanism as claimed in claim 7 wherein a series of at least four roller means are recessed within the outer surface of the lower bolster at locations adjacent to the inner surface of the lower clamping plate and arranged so that each roller is in position to support a proportionate share of the total weight of all clamping plates and die components, said roller means having a freely rotatable bearing portion adapted to project a substantial distance above said bolster surface and a spring means biasing said bearing portion above said bolster surface with sufficient force to support said proportionate die assembly weight and maintain said lower plate free of the lower bolster surface when said clamping means is deactivated.
 11. A clamping mechanism according to claim 7 wherein said clamp actuating means includes a piston mounted within an actuating cylinder in each clamp body and arranged to thrust against the clamp mounting bolster when activated to forcefully pivot the engaging surface of the clamp body against the engaged surface of the associated clamping plate.
 12. In a metal working apparatus having at least one bolster for supporting metal working die components, a clamping mechanism for securing die components in operative position upon the bolster comprising a clamping plate having an outer clamping surface along each of two opposing edges thereof; clamping means including a first clamp body pivotally mounted upon said bolster near one edge thereof and having an inner clamping surface arranged to coact in clamping engagement with one of the outer clamping surfaces on the clamping plate and a second clamp body pivotally mounted upon said bolster near the edge opposite said first clamp body and having an inner clamping surface arranged to coact in clamping engagement with the other outer clamping surface on said clamping plate; means for actuating said clamping means including a piston mounted within an actuating cylinder in each of said clamp bodies, said pistons being arranged to thrust against said bolster when activated to pivot opposing clamp bodies toward each other and bring said clamp surfaces into clamping engagement with said coacting plate surfaces to wedge the plate in operative position upon the bolster between said clamp bodies; and means for rigidly securing the die components to said clamping plate. 